Full report

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NASA Technical Memorandum 100597 SPACE STRUCTURE (DYNAMICS AND CONTROL) THEME DEVELOPMENT (LASA-TW- 1OO557) $PACE S I L R U C l C B E ( D Y N A B L C S N86-25 651) A l r D CCKTECL) ! i H E l € D E V E L O E H E B I Richard A. Russell RichardM. Gates AUGUST 1988 National Aeronauticsand Space Administration Langley ReciearchCenter Hampton,Virginia 23665-5225 (HA5.A) 32 p CSCL 228 Unclaz GJ/18 0 1648 15

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Table of Contents Section 1.o Introduction Paae 1 2.0 Technical Objectives and Goals 2 Long Range 3.0 Evaluation of On-going and ProposedActivities 4 3.1 On-going Activities 3.2 Proposed Activities 3.3 Activity Summary 3.4 Technology Gaps 4 6 7 13 4.0 Experimental Activities 18 Recommended 4.1 Prioritizationof Technology Areas 18 4.2 ExperimentTimetable 4.3 Interrelationship of Activities 5.0 Summary and Conclusions 6.0 Acknowledgements 20 21 28 29

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1.0 I n t r o d u c t i o n F u t u r e s p a c e c r a f t w i l l be l a r g e r and more complex, and t h e i r p e r f o r m a n c e r e q u i r e m e n t s w i l 1 , b e more demanding. Advancements i n many t e c h n o l o g y areas a r e needed ift h e i n c r e a s e d performance r e q u i r e m e n t s a r e t o be met. Long range t e c h n o l o g y g o a l s need t o be i d e n t i f i e d , and a l o g i c a l p r o g r e s s i o n of experiments and d e m o n s t r a t i o n s must be e s t a b l i s h e d so t h a t t h e s e g o a l s w i 11 be reached. Many t e c h n o l o g y development e x p e r i m e n t s have been proposed t h a t w i l l be conducted from t h e O r b i t e r w h i l e a t t a c h e d t o t h e Space S t a t i o n . The or d e s c r i b e d i n t h e Space S t a t i o n F l i s s i o n Space S t a t i o n e x p e r i m e n t s a r e Requirements Data Base (MRDB). Others were proposed a t t h e O f f i c e o f A e r o n a u t i c s and Space Technology (OAST) In-Space Research Technology and E n g i n e e r i n g ( R T & E ) Workshop h e l d i n October of 1985. Experiments i n seven t e c h n o l o g y ''theme areas'' were d e s c r i b e d a t t h e workshop. T h i s s t u d y addresses t h e t e c h n o l o g i e s i n t h e Space S t r u c t u r e (Dynamics and C o n t r o l ) theme area. f i r s t p a r t o f t h i s s t u d y was t o d e f i n e t h e The l o n g - r a n g e t e c h n i c a l o b j e c t i v e s and g o a l s f o r t h e Space S t r u c t u r e (Dynamics and C o n t r o l theme area. The second p a r t was t o e v a l u a t e t h e p a s t and c u r r e n t (e.p., A C C E W E A S E and COFS) and t h e proposed t e c h n o l o g y a c t i v i t i e s (e.g., r e s u l t s ) . One of t h e m a j o r p r o d u c t s of MRDB and t h e R T & E Workshop t h i s e v a l u a t i o n was t h e i d e n t i f i c a t i o n o f t e c h n o l o g y gaps and t h i n s p o t s t h a t s h o u l d r e c e i v e more a t t e n t i o n t o r e a c h t h e l o n g - r a n g e o b j e c t i v e s . The f i n a l p a r t was t o i d e n t i f y and recommend e x p e r i m e n t a l a c t i v i t i e s i n t h e 1988-2000 t i m e p e r i o d , l i s t i n g the e x p e r i m e n t s by y e a r and i d e n t i f y i n g t h e t e c h n i c a l o b j e c t i v e s o f each and t h e i r i n t e r r e l a t i o n s h i p s . 1

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2.0 Long-Range T e c h n i c a l O b j e c t i v e s and Goals The long-range 5 o a l s i n t h e Space S t r u c t u r e (Dynamics and C o n t r o ) theme a r e a r e l a t e t o t h e c o n s t r u c t i o n of s t r u c t u r a l systems i n space, t h e c h a r a c t e r i s t i c s , and t h e development of c o n t r o d e t e r m i n a t i o n of t h e i r systems and a c t u a t o r s t o p o i n t them and m a i n t a i n t h e i r c o n f i g u r a t i o n . c a t e g o r i e s o f S t r u c t u r e s , C o n t r o l / S t r u c t u r e s These g o a l s , a i v i d e a i n t o t h e I n t e r a c t i o n , and C o n t r o l , a r e l i s t e d i n F i g u r e 2-1. Technology g o a l s i n t h e s t r u c t u r e s area i n c l u d e a l l t y p e s of i n - s p a c e c o n s t r u c t i o n (e.g:, deployment, assembly and f a b r i c a t i o n ) as w e l l as methods and t e c h n i q u e s f o r r e p a i r . Development and d e n i o n s t r a t i o n o f n o n t r a d i t i o n a l methods of c o n s t r u c t i o n , such as i n f l a t a b l e s and o t h e r advanced concepts, a r e e n v i s i o n e d . T e s t methods and sensors a r e a l s o r e q u i r e d t o d e t e r m i n e s t r u c t u r a l p r e c i s i o n , dynamic c h a r a c t e r i s t i c s , damping, thermal d e f l e c t i o n s , s t r u c t u r a l loads and e n v i r o n m e n t a l e f f e c t s . S t r u c t u r a l l y - e m b e d d e d sensors and a c t u a t o r s a r e d e s i r a b l e t o enhance performance, t o reduce t h e p r o b a b i l i t y o f a c c i d e n t a l damage t o e x t e r n a l i n s t r u m e n t s and w i r i n g , and t o e l i m i n a t e t h e need f o r r o u t i n g w i r e b u n a l e s d u r i n g c o n s t r u c t i o n i n o r b i t ( n o t e : t h e c o n n e c t i o n o f t h e sensors t o a power s u p p l y and t o d a t a r e t r i e v a l systems a r e s t i l l i s s u e s t o be r e s o l v e d ) . System i d e n t i f i c a t i o n t e c h n i q u e s a r e r e q u i r e d t o d e t e r m i n e t h e s t r u c t u r a l dynamic c h a r a c t e r i s t i c s of l a r g e space s t r u c t u r e s f o r s u p p l j system i n f o r r l i a t i o r i f o r c o n t r o l systerli e n g i n e e r i n g e v a l u a t i o n and t o f u n c t i o n s . k i t h t h e i n c r e a s i n g s i z e of space s t r u c t u r e s e n v i s i o n e a f o r t h e f u t u r e , t h e importance of c o n t r o l / s t r u c t u r e s i n t e r a c t i o n a l s o i n c r e a s e s . S t r u c t u r a l f r e q u e n c i e s a r e lower ana can f a l l w i t h i n t h e b a n d w i d t h of t h e c o n t r o l l e r , rilakiny t h e t a s k of s t a b i l i z i n y , c o n t r o l l i n g , maneuvering, a r t i c u l a t i n g , p o i n t i n g , m a i n t a i n i n g s t r u c t u r a l a l i g n m e n t , ana m i t i g a t i n g t h e e f f e c t s of i n t e r n a l a n d e x t e r n a l d i s t u r b a n c e s much more a i f f i c u l t . The c o n t r o l p h i l o s o p h i e s ana t e c h n i q u e s t o a c c o m p l i s h t h e s e t a s k s need t o b e developed ana aeinonstratea. The dynamics ana c o n t r o l of t e t h e r e a systems a l s o need t o be u n d e r s t o o d anu demonstrated i n o r b i t . a c t u a t o r t e c h n o l o g y needs t o be advancea t o C o n t r o l system sensor and meet ever i n c r e a s i n g a c c u r a c y and p r e c i s i o n p o i n t i n g r e q u i r e i n e n t s over a wide range o f f r e q u e n c i e s . C o n t r o l t e c h n i q u e s , p a r t i c u l a r l y i m p o r t a n t f o r developed i n c l u d e s t a t i o n k e e p i n g (PIMU, OMV, Space S t a t i o n , t h a t need t o be STS, f r e e - f l y e r s ) , maneuvering (MF111, OFiV, STS), d o c k i n g ana b e r t h i n 9 ( S T S , OMV, N U ) , r o b o t i c s ( i n s p e c t i o n , s e r v i c i n g , c o n s t r u c t i o n , maintenance and r e c o n f i y u r a t i o n ) , dnd t a i l u r e a e t e c t i o n and i s o l a t i o n . 2

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Figure 2-1: Long Range Technical Objectives and Goals, Space Structures (Dynamics and Control ) Structures In-Space Construction Deployment, Assembly, Fabrication Modi fi cation/Repai r Advanced Structural Concepts Structural Characterization As-bui 1 t Accuracy Dynamics & Loads Characterization Damping Evaluation (joints, passive, etc.) Environmental Effects Test/NDE Methods Control/Structure Interaction Structural 1y Embedded Sensors/Actuators System Identi fication Control o f Large, F1 exi ble Structures Stabi 1 ity Pointing Articul at1on Modal control Maneuvers/sl ewi ng Shape and Figure Control Dynamics and Control of Robots & Manipulators Disturbance Control Vi bration Isol at i on F1 uid/Structure Interaction Tether Dynamics Control Technology Distributed, Multi-loop, Hierarchical, Adaptive Modeling, Synthesis and Analytical Tools Controls Sensors & Actuators Improved Actuator Efficiency (e.9.. torque/mass, force/mass) High Accuracy Surface Sensor (Mu1ti -DOF) Real -Time Photogrammetric Concepts Mi d-Range Momentum Actuators High Speed, High Capacity Flight Computers for CSI High Speed, High Capacity Data Bases Mu1 ti -Body A1 ignment Transfer & Pointing Systems Re1 ative A1 i gnment Sensor Vi bration Actuators Low-Frequency Actuators Optical/Inertial Vi bration Sensors Low-G Accelerometers Low-Thrusters for Reboost Control Technol ogy Station keeping Maneuvering Docki ng/Berthing Roboti cs Failure Detection, Isolation and System Reconfiguration Guidance for Proximity Operations and Sate1 1 i te Retrieval 3

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3.0 E v a l u a t i o n of On-going and Proposed U c t i v i t i e s T h i s s e c t i o n p r o v i d e s an o v e r v i e w o f p a s t , c u r r e n t and proposed f l i g h t e x p e r i m e n t s t h a t r e l a t e t o t e c h n o l o g i e s w i t h i n t h e Space S t r u c t u r e (Uynamics ana C o n t r o l theme area. A s i g n i f i c a n t airlourit o t r e s e a r c h , development dnd t e s t i n g i s b e i n g conductea i n many areds t o p r o v i a e t h e t e c h n i c a l basis f o r t h e s e e x p e r i m e n t s . However, t h i s r e v i e w covers o n l y S h u t t l e f 1i g h t t e s t s and proposed Space S t a t i o n e x p e r i m e n t s . 3.1 On-going A c t i v i t i e s P r i o r t o t h e C h a l l e n g e r a c c i d e n t , two e x p e r i m e n t s were performed f r o m t h e S h u t t l e t h a t demonstrated s t r u c t u r e s and c o n t r o l s theme t e c h n o l o g i e s : t h e S o l a r Array F l i g h t Experiment (SAFE) and t h e E A S E / A C C E S S e x p e r i m e n t s . The C o n t r o l o f F l e x i b l e S t r u c t u r e s (CUFS) s e r i e s o f experiments w i l l be f l o w n a f t e r S h u t t l e f l i g h t s resume. 3.1.1 S o l a r A r r a y F1i y h t Experiment (SAFE) SAFL (OAST-1) was conducted on S T S M i s s i o n 41-0 on August 31, 1964. I t s p r i m a r y o b j e c t i v e were ( 1 ) t o aemonstrate t h e r e a d i n e s s , dnd a e t e r w i n e t n e performance of a l a r g e low c o s t , 1i y h t w e i g h t , dep l o y a b l e l r e t r a c t a b l e p h o t o v o l t a i c s o l a r a r r a y ; ( 2 ) t o demonstrate rriethods t o d e f i n e t h e s t r u c t u r a l dqnariiic b e h a v i o r of l a r g e space s t r u c t u r e s ; and ( 3 ) t o e v a l u a t e s o l a r c e l l c a l i b r a t i o n t e c h n i q u e s as w e l l as c a l i w a t e v a r i o u s t y p e s o f s o l a r c e l l s . Two measurement systems were used t o d e t e r m i n e s t r u c t u r d l d e f o r m d t i o n s : a photo-gramirietric systern t h a t deterirkifled t h e 3-dimensiond 1 l o c a t i o n of t a r g e t s u s i n g f o u r c l o s e d c i r c u i t t e l e v i s i o n ( C C T V ) cameras f o r t r i a n g u l a t i o n , and a Oynamic Augmentation t x p e r i m e n t ( L J A t ) l a s e r measurement system. The deployment ana r e t r a c t i o n o b j e c t i v e s of t h e 32 x 4 meter s o l a r a r r a y were s u c c e s s f u l l y achieved, and measurenents of s o l d r a r r a y m o t i o n were o b t a i n e d . P r e f l i g h t p r e d i c t i o n s o f t h e dynamic c h a r a c t e r i s t i c s were v e r i f i e d w i t h f 1i g h t measurements, however t h e measurea s t r u c t u r a l danlping was h i g h e r t h a n p r e d i c t e a (3.5 p e r c e n t vs 0.5 p e r c e n t ) . The SAFE s o l a r a r r a q b l a n k e t a l s o e x h i b i t e d unexpected c u r v a t u r e a u r i n g t h e dark p o r t i o n s of t h e o r b i t , and p e r s i s t e n t low f r e q u e n c y o s c i l l a t i o n s were e x p e r i e n c e d . These unexpectea r e s u l t s d e w n s t r a t e t h e v a l u e o f o n - o r b i t d e m o n s t r a t i o n t e s t s . 3.1.2 tASt/ALCt.SS These t w o e x p e r i m e n t s were f l o w n on S T S M i s s i o n 61-11 o n November 26, 1985. t x p e r i m e n t a l Assembly o f S t r u c t u r e s i n E V A ( E A S E ) The EASE e x p e r i m e n t c o n s i s t e a of r e p e a t e d E V A assembly and d i s a s s e m b l y o f a s i x - e l e m e n t t e t r a h e d r o n , u s i n g s t r u t s 3.6 m l o n g . The d s t r o n a u t s were u n c o n s t r a i n e d (no f o o t r e s t r a i n t s ) d u r i n g t h e a s s e i l i b l j 4

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process. T i m e l i n e s were o b t a i n e d and compared w i t h t h o s e o b t a i n e d d u r i n g t e s t s conducted i n a n e u t r a l buoyancy s i n i u l a t o r on E a r t h . F l i g n t t e s t r e s u l t s show t h a t most of t h e a c t i v i t i e s were accomplished more r a p i d l y i n space t h a n t h e y were i n n e u t r a l buoydncy t r a i n i n g . Assembly Concept f o r C o n s t r u c t i o n o f E r e c t a b l e Space S t r u c t u r e s ( A c L L S S ) The O b j e c t i v e of t h e A C C E S S f l i g h t e x p e r i m e n t was t o Study t h e o r b i t a l assembly of a space t r u s s . A 10 bay t r u s s beam s t r u c t u r e , 45 f e e t l o n g was assembled by t w o E V A a s t r o n a u t s i n f i x e d f o o t r e s t r a i n t s . A f i x e a work s t a t i o n ; assembly l i n e method was usea t o assemble t h e 93 t u b u l a r s t r u t s and 33 noaal j o i n t s . I n t h e Second p o r t i o n of t h e e x p e r i n t e n t , an a s t r o n a u t i n t h e n i o b i l e f o o t r e s t r a i n t ( M F R ) , a t t a c h e d t o t h e remote m a n i p u l a t o r system (RMS), dernonstrated s t r u c t u r a l assembly ana r e p a i r o f space s t r u c t u r e s , t h e i n s t a l l a t i o n of c a b l e s , and t h e manual m a n i p u l a t i o n o f t h e t r u s s beani. A l l o f t h e t a s k s were s u c c e s s f u l l y completed, and t h e c o n s t r u c t i o n t i m e s agreed w e l l w i t h n e u t r a l buoyancy t r d i n i n g s i r l u l a t i o n s . The a s t r o n a u t s p r e f e r r e a t h e c o n s t r a i n e a w o r k s t a t i o n assembly c o n c e p t u s e d d u r i n g A C C E S S o v e r t h e f r e e - f l o d t i n g E A S E assembly method. 3.1.3 C o n t r o l o f F l e x i b l e S t r u c t u r e s ( C O F S ) COFS i s a t h r e e phase program whose o v e r a l l O b j e c t i v e i s t o d e v e l o p and v a l i d a t e t h e t e c h n o l o g y d a t a base r e q u i r e d f o r c o n t i a e n c e i n t h e d e s i g n aria c o n t r o l s p a c e c r a f t by t h e m i a 1 9 9 0 ' s . The approach o f l a r g e f l e x i b l e i s t o d e v e l o p and v a l i d a t e design and a n a l y s i s t o o l s , t o d e v e l o p and d e m o n s t r a t e ground t e s t methods, ana t o conauct g e n e r i c i n - s p a c e e x p e r i m e n t s t o v a l i d a t e t h e ground t e s t s and a n a l y s i s . COFS I COFS I c o n s i s t s of t h e Mast F l i g h t System, a t r i a n y u l d r c r o s s - s e c t i o n , beam. It i s 6U.4 m e t e r s i n l e n g t h ( f u l l y j o i n t doriiinated, a e p l o y a b l e t r u s s d e p l o y e d ) , 1.4 m e t e r s i n didmeter, and i s made up o f 54 bays. It i n c l u d e s d 180 k y t i p mass t h a t a l s o c o n t a i n s p r i i n a r y a c t u a t o r s , c o l l o c a t e d sensors, subsystem. Deployment w i l l De accomplishea i n and a parameter m o d i f i c a t i o n two-bay i n c r e m e n t s f roni a aep loyment c a n i s t e r system. Sensors and proof-mass a c t u a t o r s d i s t r i b u t e d a l o n y t h e beam w i l l De used f o r a j n a m i c parameter i d e n t i f i c a t i o n , f o r i n t r o d u c i n g darnpiny i n t o t h e s t r u c t u r e , and f o r t h e development o f a i s t r i b u t e d c o n t r o l s t e c h n i q u e s . I n a d d i t i o n t o t h e b a s i c experiment, a g u e s t i n v e s t i g a t o r program has been initiates by NASA L a n g l e y kesearch Center (LaRC) t o a l l o w i n d u s t r y and u n i v e r s i t i e s t o suggest and d e v e l o p ground t e s t s and f l i g h t e x p e r i i i i e n t s t h a t c o u l d be conductea u s i n g t h i s f l i g h t a r t i c l e . S c a l e inoael ground t e s t s a r e dlso p l a n n e d t o develop s c a l e model t e s t i n g t e c h n i q u e s t h a t can be a p p l i e d t o s t r u c t u r e s t o o l a r g e o r f r a g i l e t o be t e s t e d i n f u l l s c a l e on t h e ground. CUFS I 1 expanas on t h e COFS I Mast e x p e r i m e n t a l hardware by a t t a c h i n g a s h o r t beam, a t w o - a x i s gimbal system and a 15 meter d e p l o y a b l e hoopcolumn antenna t o i t s t i p . The o b j e c t i v e s a r e t o aevelop ana e v a l u a t e t h e 5

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methodologies i n v o l v e d i n m o d e l i n g and c o n t r o l l i n y l a r g e , f l e x i b l e , 3-dimensional s t r u c t u r e s i n space. I n t h e area of s t r u c t u r a l dynamic c h a r a c t e r i z a t i o n , the y o a l s a r e t o measure deployment ayriamics, t o p e r f o r i l l s t r u c t u r a l e v a l u d t i o n s , t o a c c o w p l i s h systeiii i a e n t i t i c a t i o n , aria t o e v a l u a t e f a u l t d e t e c t i o n , i s o l a t i o n and r e c o v e r y methods. Systenis c o n t r o l y o a l s a r e t o d e m o n s t r a t e a l i g n m e n t ana shape c o n t r o l , v i b r a t i o n suppression, p o i n t i n g ( L O S s t a b i l i z a t i o n ) , a r t i c u l a t i n 9 and s l e w i n g , a d a p t i v e c o n t r o l , ana maneuver l o a d a1 l e v i a t i o n . Development and ground based t e s t s of a 15-meter hoop-column antenna, c u r r e n t l y i n p r o g r e s s a t LaRC. Many C W S i t s coniponents and subsystems a r e r e l a t e d t e c h n o l o y i e s a r e under aevelopment, i n c l u d i n q trlethods f o r measuring f o r p o i n t i n g and s l e w i n g ( S C O L € ) , and f o r and a d j u s t i n g r e f l e c t o r s u r f a c e s , f a u l t d e t e c t i o n and i s o l a t i o n . COFS 1 1 1 The t e c h n o l o g y g o a l s f o r COFS 111 a r e t o v a l i d a t e c o n t r o l / s t r u c t u r e s i n t e r a c t i o n ( C S I ) a n a l y s i s t o o l s f o r m u l t i p l e - b o d y concepts, t o e v a l u a t e m o d e l i n g s e n s i t i v i t i e s , t o d e v e l o p v i b r a t i o n s u p p r e s s i o n methods, t o d e v e l o p ground t e s t methods, t o c o r r e l a t e s c a l e d ground t e s t s w i t h f u l l - s c a l e f l i g h t data, and t o p r o v i a e t i t n e l y development of Space S t a t i o n s u p p o r t i n g t e c h n o l o g y . The v e h i c l e t o be used t o a c c o m p l i s h t n e s e y o a l s w i l l be a d y n a m i c a l l y s c a l e a model of t h e Space S t a t i o n t h a t N i l 1 u s e modular c o n s t r u c t i o n f o r b u i l d u p stages, i n t e r c h a n g e a b l e elements, r e a l i s t i c j o i n t s and members, manual a r t i c u l a t i n g j o i n t s , and r e a l i s t i c a l l y a t t a c h e d pdyloaus. A L a r y e S p a c e c r a f t L a b o r a t o r y ( L S L ) t a c i l i t y a t LaHC i s b e i n g planned t o accomniodate t h e ground t e s t i n g of t h i s s c a l e model, 3.2 Proposea A c t i v i t i e s Proposeu a c t i v i t y f o r development and d e m o n s t r a t i o n o f space systems t e c h n o l o g y i s containecl i n t h e Space S t a t i o n N i s s i o n Requirements Uata Base IviHUB) ana i n t h e r e b u l t s of t h e GAST In-Space kesearcti, Technoloyy and L n g i n e e r i n g korksnop. T h i s s e c t i o n a e s c r i b e s t h e s e t c o sources o f t e c h n o l o g y aeve 1opment e x p e r i m e n t s . 3.2.1 T O M X h i s s i o n s Near t h e b e g i n n i n g o f t h e Space S t a t i o n d e f i n i t i o n ( i n t h e e a r l y 198O's), NASA s o l i c i t e d i d e a s f r o m i n d u s t r y , u n i v e r s i t i e s , NASA c e n t e r s ana f o r e i y n c o u n t r i e s f o r t e c h n o l o g y development e x p e r i m e n t s and m i s s i o n s t h a t t h e Space S t d t i o n . T h i s l i s t became can be conducted on o r deployed f r o m t h e b a s i s f o r t h e Space S t a t i o n M i s s i o n h e q u i r e m e n t s Data Base ( F I F I U B ) , t h a t Space S t a t i o n . NASA e f f o r t s and s t u a y h e l p e d t o d e f i n e t h e need f o r a c o n t r a c t s have r e s u l t e d i n more a e t a i l e d d e f i n i t i o n s o f t h e s e e x p e r i m e n t s . The MKDb i s d i v i d e d i n t o f o u r i i i i s s i o n c a t e g o r i e s : Commercial (CUCIM), Science ana A p p l i c a t i o n s (SAAX), Technology Ueveloptnent ( T U M X ) , and F o r e i g n . This s t u d y w i l l c o n s i d e r o n l y t h e TDPIX m i s s i o n s , a l t h o u g h t h e o t h e r m i s s i o n s h e l p t o i a e n t i f y areas f o r which t e c h n o l o g y development i s 6

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r e q u i r e d . There a r e c u r r e n t l y 7 4 TDMX m i s s i o n s i n t h e MRDB, w i t h s e v e r a l o t h e r s b e i n g c o n s i d e r e d . Of these, 2 3 m i s s i o n s a r e i n t h e Space S t r u c t u r e s a r e a . NASA has i d e n t i f i e d 7 of these m i s s i o n s as c a n d i d a t e s t h a t w i l l most l i k e l y be conducted i n t h e I O C time-frame, i.e. w i t h t h e f i r s t t h r e e y e a r s a f t e r Space S t a t i o n I O C ( I n i t i a l O p e r a t i o n a l C a p a b i l i t y ) . These e x p e r i m e n t s range f r o m t e s t s of sensors and components t o t h e c o n s t r u c t i o n s and t e s t of l a r g e space s t r u c t u r e s ( i n c l u d i n g p o r t i o n s of Space S t a t i o n f a c i l i t i e s ) , and from t h e d e m o n s t r a t i o n o f Space S t a t i o n o p e r a t i o n a l c a p a b i l i t i e s t o t h e d e t e r m i n a t i o n of t h e space e n v i r o n m e n t and i t s e f f e c t on o r b i t a l systems. 3.2.2 R T & E Workshop R e s u l t s On October 8-10, 1985, NASA L a n g l e y Research Center h o s t e d an OAST In-Space Research, Technology and E n g i n e e r i n g (RT&E) Workshop h e l d i n W i l l i a m s b u r g , V i r a i n i a . The purpose of t h e workshop was t o b r i n g t o g e t h e r r e p r e s e n t a t i v e s of t h e u n i v e r s i t y community, t h e p r i v a t e s e c t o r , and government agencies t o d i s c u s s f u t u r e needs f o r in-space experiments, i n s u p p o r t o f space t e c h n o l o g y development. The r e s u l t i n g e x p e r i m e n t s , i n seven theme areas, a l s o s e r v e t o d e f i n e r e q u i r e m e n t s f o r Space S t a t i o n f a c i l i t i e s t o s u p p o r t i n - s p a c e R T & E . The theme area t h a t w i l l be c o n s i d e r e d i n t h i s s t u d y i s "Space S t r u c t u r e (Dynamics and C o n t r o l 1.'' I n t h e Space S t r u c t u r e (Dynamics and C o n t r o l ) theme area, t h e r e were 3 1 e x p e r i m e n t s d e s c r i b e d , 16 o f which were TDMXs a l r e a d y l i s t e d i n t h e MRDB. The e x p e r i m e n t s p r e s e n t e d were c a t e g o r i z e d i n t o f i v e key t e c h n o l o g y a r e a s : component t e c h n o l o g y , c o n t r o l / s t r u c t u r e i n t e r a c t i o n , Space S t a t i o n dynamic c h a r a c t e r i z a t i o n , Space S t a t i o n c o n s t r u c t i o n t e c h n o l o g y , and advanced. s t r u c t u r a l concepts. An eleven-member p a n e l r e v i e w e d t h e e x p e r i m e n t s p r e s e n t e d t o determine t e c h n o l o g y gaps, t h e need f o r in-space t e s t s , impacts t o t h e Space S t a t i o n , and c r i t i c a l areas f o r development. The workshop assessment i s a major i n p u t t o t h i s s t u d y . 3.3 A c t i v i t y Summary The e x p e r i m e n t s l i s t e d i n t h e M R D R and t h o s e proposed a t t h e O A S T In-Space R T & E Workshop a r e summarized and d i s c u s s e d i n t h i s s e c t i o n . Technology qaps n o t e d b y t h e R T R E Workshop p a n e l and o t h e r s r e s u l t i n g f r o m a r e v i e w o f ' t h e e x p e r i m e n t s a r e a l s o i d e n t i f i e d . 3.3.1 Proposed Fxperiments The e x p e r i m e n t s proposed a t t h e O A S T In-Space RT&E Workshop were experiments l i s t e d i n t h e MRDB. A c o m p o s i t e r e v i e w e d and compared w i t h t h e l i s t o f t h e s e experiments, grouped i n t o t h e f i v e c a t e g o r i e s used a t t h e Workshop, i s shown i n F i g u r e 3.3.1-1. The f i g u r e l i s t s t h e t i t l e of each e x p e r i m e n t , i t s TDMX number ( i f it has one), t h e s o u r c e of t h e e x p e r i m e n t d e s c r i p t i o n , and i t s proposed f l i g h t schedule. Many of t h e e x p e r i m e n t s were i n c l u d e d i n b o t h t h e TDMX l i s t and t h e Workshop. W i t h i n each c a t e g o r y , t h e e x p e r i m e n t s a r e l i s t e d i n c h r o n o l o g i c a l o r d e r based on t h e ( y e a r ) . A t t h e t i m e t h a t most of t h e o p i g i n a l l y - p r o p o s e d f l i g h t d a t e 7

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Figure 3.3.1-1: PROPOSED SPACE STRUCTURE (DYNANICS & CONTROL) EXPERINENTS I EXPERINENT \ PROPOSED FLIGHT )I 1 I I I I YEAR I II I TDHX : REF. I 88: 891 90: 91It92: 931 941 95: 96: 97: 98: 99I2000: I I 1. COHPONENT TECHNOLOGY I I I 1: Berthino and Docking Sensor I I 2. Fiber Optic Sensors i n Space Apolic. I 1 I I I I I I I I I I I I I I 1 1 1 1 1 0 1 1 1 1 1 1 I 1 2 I X : : I I I I I I I I I I I I Z I I : I : : ; ; I I : I I I I I 3. S / C S t r a i n k Acoustic Sensors I 2 0 7 2 : 1 , 2 I I I I I X : I I II 'I 'I II II I I 4. A t t i t u d e Control k Enerov F l i u h t EXR. I I 2 : I : I : X I ; : : : : I I I I 2 4 2 2 : 1 , 2 I I I : I X : I I I I I I I I 5. Therral Shaoe Control 2432 I 1,2 I I I I I X I I I I I I I I I 6. Advd. Expmt. P o i n t i n p and I s o l a t i o n I 2 4 3 1 I 1 , Z I I I : I I : X I I I ! I I I I 7. Advanced Control Device Technolow I 8 I I I I 2. CONTROCISTRUCT. INTERACTION EXPERINENTS I 1 I 1. COFS F l i o h t Experiments I : 2. In-Space Activelv C o n t r o l l e d Struct. I , I l I l I I I I I I I l l I I I I I I I I I I I I l I l I I 1 1 l 1 1 1 1 1 1 1 l 1 1 I I I 1 1 1 1 1 1 1 1 1 1 1 1 I I 2 : : x I x : x : x : I I I I I I I I : 2 I : x I I I I I I I I I I I : I 2 0 7 1 : 1 , 2 I I I I : X I I I I : I I I 3. F l i o h t Dvnaaics I d e n t i i i c a t i o n I 4. Active ( i o t i c T e C h I I O l O Q Y I 2 4 2 1 1 1 I I I I I X I X I I . I I I I I I I 5. Advanced Adaotive Control 2 4 1 1 : 1 , 2 I I I I I : X I I I I I I I I I 2 4 1 2 1 1 . 2 : I I I I ; X I I I I I I I I I 6. D i s t r i b u t e d Control Experiment : ? 4 1 3 ! 1 , 2 I I I I : : X I I I I I I I I I 7. Dvnaric Disturbance Control I I 8. Tethered Exoerinents I2541-41 1 : I I I I I : X I I X I X I X I I X I I 9. Dvnanic S t a b i l i z a t i o n of FIF kobot I 2433 I I I 0 I 3. SPACE S T A T I O N DYNAHIC CHARACTERIZATION I 1 1 I : I I I I I I I X I I I I I I I I l l l l l l l l l l l I I 1 1 1 1 1 1 1 1 1 l 1 1 1 I I I I I I I I I I I I I I I I I 1 1 1 l 1 1 1 1 1 1 1 1 1 I : 1. Advanced Controls Technolow I 2 4 1 4 I 1 . 2 I I I I I X I I I I I I I I I I I 2. So. Sta. Svster Perf. Technolow I I I , 1 I 4. SPACE CONSTRUCTION TECHNOLOGY I I 1. Struct. b As5v. V e r i f . Exp. ( S A V E ) I I I 2 I I I I I I x : x I x I x : x I x : x I x : I 1 1 1 1 1 1 1 1 1 l 1 1 1 I I I I I I I I I I I I I I I I ,, 1 1 l 1 1 1 1 1 1 l I l I I 1 1 1 1 l 1 1 1 1 l I I I I 1 2 1 I : I x : I : : : I : I : I I 2. Laroe Soace Structure I ? O L 1 1 1 , 2 I I I I : X I I : I I I I I I 2 0 6 2 I 1 . 2 I I I : I X I I I I I I I I I I 3. Soace Station H o d i f i c a t i o n s I 2 0 6 3 1 1 . 2 I I I I I I I I I I : I I I I I 4. On-Orbit SIC Asserblv k Test I : 5. Laroe Soace Antenna (Reflectors) I I 6. Environ. Influence on Struct. Dvnamics: : 7. Precision Ootical I I 8. TDN for LDR , : 2 I I I I I I X I X I I X I X I I I I 1 2 1 1 , ' l 8 I s l ' I X I I I I I I I I I I I I ~ 1 2 1 1 , 1 , 1 1 x I I : : I : I I 2 1 I I I I : I : X I I I I I I I 9. I n f l a t a b l e l R i o i d i z a b l e Struct. Element; 2066 I 1.2 I I I I I I I I k I I I I I I I l l 1 : 10. Laroe Deolovable R e f l e c t o r (LOR) ISAAX521) I * , , , ; : : : : : X I : : : I 11. bdv. Antenna Assenblv/Performance I 2064 I 1,2 I I I I : I I I I I x I 1 I 8 I 0 I I I 5. NATERIALS k F A B R I C A T I O N TECHNOLOGY I ; ? I ; x : ; ; II lt II II 4t II 1I 1I Ib I 1. Polvaeric Hat'15 for Soace Hechanisms : q I 2. Soacecraft H a t e r i a l s k Coatinas : Q l 1 : : 3. Micrometeorite P r o t e c t i o n , 1 I I I I I I I I I I I I I a I , I l I , I , , I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 1 I I I I ; X I I I I I I I I I t 2 I I I I ; I I I a I : I ; r I : 4. Ion beaa C o l d Yeldino 1 ? 3 6 5 : 1 , 2 : I I I I I I I I I I I I 6. STRUCTURAL CONCEPTS RESEARCH FACILITY I t O r i o i n a l l v assumed Soace S t a t i o n 10C 1 Soace Station Hission Reouirenents Data base (KRDb) : ? : I : I : I I I I I I : 2 In-Space Research, Technology and Enaineering (RT&E) norkshop a

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e x p e r i m e n t s were proposea, t h e year o f Space S t a t i o n I n i t i a l U p e r a t i o n C a p a b i l i t y ( I O C ) was assumed t o be 1992. A b r i e f d e s c r i p t i o n o t t h e p r i m a r y o b j e c t i v e s of each o f t h e e x p e r i m e n t s , i n t h e Space S t r u c t u r e (Uynainics and C o n t r o l ) theine a r e a , i s shown i n F i g u r e 3.3.1-2. 3.3.2 O b s e r v a t i o n s The r e v i e w of t h e proposed experiments r e v e a l e d t e c h n i c a l o b j e c t i v e s t h a t d u p l i c a t e d , o v e r l a p p e d o r complementea each o t h e r . Also, s e v e r a l o f t h e e x p e r i m e n t s s u p p o r t e d t e c h n o l o g y development i n d i f f e r e n t areas b u t c o u l o be c o n t r i b u t o r s t o t h e saiiie p r o j e c t . The f o l l o w i n g p a r a g r a p h s d i s c u s s t h e s e o b s e r v a t i o n s f o r each of t h e e x p e r i m e n t s . 3.3.2.1 Component Technology B e r t h i n g and Docking Sensor - Development of t h e s e sensors s h o u l a b e c o n d u c t e d i n c o n j u n c t i o n s w i t h b e r t h i n g and d o c k i n g mechanism developiilent ana ground t e s t s . A Space S h u t t l e a e n i o n s t r a t i o n m i s s i o n rieeds t o b e d e f i n e d f o r t h i s sensor system. F i b e r O p t i c Sensors i n Space A p p l i c a t i o n - A o e m o n s t r a t i o n m i s s i o n needs t o be d e f i n e d f o r t h e f i b e r - o p t i c gyro a f t e r ground-based development. F i b e r - o p t i c e l o n g a t i o n sensors c o u l d be used on t h e S A V E experirnent and, p o s s i b l y , COFS I 1 t o demonstrate t h e t e c h n o l o g y f o r Space S t a t i o n . S p a c e c r a f t S t r a i n ana A c o u s t i c Sensors, TUMX2072 - S A V t a n d / o r COFS I 1 can be used as t e s t b e d s f o r t h e a e m o n s t r a t i o n of s t r a i n ana a c o u s t i c e n i i s s i o n sensors. A c o u s t i c sensors would be used f o r Space S t a t i o n m o n i t o r i n g , e.g., t r u s s i n t e g r i t y and m i c r o m e t e o r o i d / d e b r i s impact d e t e c t i o n and t r i a n g u l a t i o n i n common modules. A t t i t u d e C o n t r o l and t n e r y q F l i g h t Experiment - A m i s s i o n a u r 3 t i o n o f a t l e a s t 30 aays i s r e q u i r e d t o s a t i s f q f l i g h t t e s t o b j e c t i v e s , i.e., it r e q u i r e s t h e Space S t a t i o n o r a f r e e - f l y e r . T h i s e x p e r i m e n t i s s i m i l a r t o TUMX2431, Udvancea C o n t r o l Device Technology. Thernial Shape C o n t r o l , TUClX 2422 - A l t h o u g h t h i s experiirient i s d e s i g n e d t o be conducted on t h e Space S t a t i o n , t h e t e c h n o l o g y c o u l d be demonstrated or1 S A V E o r COFS 11. Advanced t x p e r i i r i e n t P o i n t i n g and I s o l a t i o n , TUMX2432 - L i i r i i t e a t e s t i n g O r b i t e r p r i o r t o IOC. p r o b a b l y Could be conducted on t h e TbMX2431 - S i m i l i a r t o " A t t i t u d e Advanced C o n t r o l D e v i c e Technology, t x p e r i m e n t ," above, p r e s e n t e a a t t h e O A S T C o n t r o l and t n e r g y F1i g h t In-Space H T & E Workshop: 9

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Fiaure 3.3.1-2: PRIRARV ObJECTlVES OF PRUPOSED SPACE STitUCTURE (DYIIANICS !1 C O N T H O L ) EIPERIHENTS I I I 1. CONPONENT TECHNOLOGY I I IL , I. Berthina and Docking Sensor II I1 Demonstrate berthing & docking techniques I I II II 2. Fiber Optic Sensors in Space Applic. : I, Fiber optic gyro & sensor development 1 II 3. SIC Strain & Acoustic Sensors I 2072 1 NDE rethodology developrent II II 4. Attitude Control & Energy Flight Exp. I II Develoo CH6 for attitude control energy storage II 0I 5. Theraal Shape Control : 2422 I Shape control using distributed thermal controllers II I 6. Advd. Exprt. Pointing and Isolation I 2432 I Precision pointing, disturbance suppression I1 0I 7. Advanced Control Device Technology ; 2431 : Evaluate combined energy storage Q romentun device I 1 1I I I : 2. CONTROL/STRUCT. 1NTERACTlON EXFERIHENTS I II ,I 1I I 1. COFS F l i g h t Experirent s I II Syster identification, test method development I I II I 2. In-Space Actively Controlled Struct. I I Control of alignrent, dynarics, precision pointing 8I ; 3. Flight Dvnarics ldentif ication I 2071 I Syster identification, sensor architecture & testing II : 4. Active Optic Technology I 2421 I Asserbly & operation of segmented optics system I 5. Advanced Adaptive Control I 2411 Adaptive control techniques, strategy & algorithrs I I I 4. Distributed Control Ex per inent I 2412 : Distributed control techniques, strategy 4 algorithms II I 7. Dynamic Disturbance Control I 2413 I Disturbance suppression & isolation 1I : e. l e ther ed Ex per iments 1 2511-4: Develop technology for tethers II I 9. Dynamic Stabilization of FIF Robot I 2433 I Free-flyer s t a b i l i t y II I I II I 3. SPACE STATION DYNAHIC CHARACTERIZATION I k station keeping LI II II : 1. Advanced Controls Technology I 2414 I Dvnarics & control o f large, flexible spacecraft II : 2. Sp. Sta. Syster Perf. Technology : 1I Verify & validate analysis & pre-flight predictions I I I I I , I I 4. SPACE CONSTRUCTlON TECHNOLOGY 1 I II I II I 1. Struct. & Assy. Verif. Exp. (SAVE) I E V A assembly & characterization of S.S. truss & u t i l i t i e s II 1 2. Large Space Structure I 2061 I Deploy & characterize planar truss (SS f a c i l i t y ) II ; 3. Space Station Modifications I 2062 I Space Station structural evolution (servicing area) II : 4. On-Orbit S/C Asserblv & Test I 2063 ; Spacecraft asserbly & checkout on the Space Station I I II I 5. Large Space Antenna !Reflectors) I I Antenna deployment, assembly L characterization II II I 6 . Environ. Influence on Struct. Dynaricsl Deteriine long-term effects o t space environment I I II I 7. Precision Optical I I Asserbly, alignrent & dynamics of segmented optics I I II I 8. TDH for LOR I I Deploy, align and control segmented optics II I 9 . InflatableIRiqidizable Struct. Element: 2066 : Developrent of advanced structural concepts II : 10. Large Deployable Reflector ( L D R ) IsAAro2or):Construct & operate large seqrented Optics System 1I : 11. Adv. Antenna Asserbly/Perforaance I 2064 Asserble & characterize lOOa did. antenna I I I 1 I I I I 5 . HATERIALS & FABRICATION TECHNOLOGY I I 1 I I I 1. Polyreric Hat'ls for Space Hechanisrs I II Effect of space environment on material performance I 2. Spacecraft Haterials & Coatings : 2011 : Determine effect of space env. on r a t e r i a l s t coatings : II : 3. Hicroreteorite Protection I II Hicroreteorit e protect ion technique development I 4. Ion Bear Cold Melding I 2065 : Develop ion beam welding tech. for in-space fabrication I I I I I I I II I : 6. STRUCTURAL CONCEPTS RESEARCH FACILITY : Facility t o study structural concepts & components I I I I I II 1 0

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3.3.2.2 C o n t r o l / S t r u c t u r e s I n t e r a c t i o n Experiinents COFS F l i g h t E x p e r i m e n t s - As discussed i n S e c t i o n 3.1.3, t h e s e e x p e r i m e n t s w i 17 s a t i s f y some of t h e g o a l s t o r b o t h s t r u c t u r e s ana c o n t r o l / s t r u c t u r e i n t e r a c t i o n . In-Space A c t i v e l y C o n t r o l l e d S t r u c t u r e I- T h i s e x p e r i m e n t i s d t e s t b e a f o r a number o f t e c h n o l o g y d e m o n s t r a t i o n s ( s t r u c t u r a l a l i g n m e n t , a i s t u r b a n c e a t t e n u a t i o n , p r e c i s i o n p o i n t i n g ) . TDMX2071 - The antenna hardware used f o r F l i g h t Dynamics I d e n t i f i c a t o n , t h i s e x p e r i m e n t i s a l s o used on TDMX2411, 2412, 2413, and t h e " L a r g e Space Antenna ( k e f l e c t o r s ) " experiment. TUkX2423l - T h i s experiinent was n o t p r e s e n t e a a t A c t i v e O p t i c Technology, t h e OAST In-Space kT&E korkshop. It s u p p o r t s L a r g e O e p l o y a b l e R e f l e c t o r (LUH) t e c h n o l o g y g o a l s . It i s s i m i l a r t o " P r e c i s i o n G p t i c a l " ana ma) be t h e same as "TUM f o r LDk," a l t h o u y h d i f f e r e n t f l i g h t u d t e s a r e l i s t e d . Advanced A d a p t i v e C o n t r o l , TUMX2411 - The antenna hardware i d e n t i f i e d f o r t h i s e x p e r i m e n t i s a l s o used on TUMX 2071,2412, 2413, and t h e "Large Space Antenna ( Ref l e c t o r s ) .'I O i s t r i b u t e d C o n t r o l Experiment, TUMX2412 - The antenna hardware i d e n t i f i e d f o r t h i s e x p e r i m e n t i s a l s o used on TUMX2071,2411, 2413, and "Large Space Antenna ( R e f l e c t o r s ) . " Dynamic D i s t u r b a n c e C o n t r o l , TDMX2413 - The e x p e r i m e n t i s c a l l e d " L a r g e C o n t r o l " a t t h e O A S T In-Skace K T & E k'orkshop. Space S t r u c t u r e s D i s t u r b a n c e The antenna haraware used f o r t h i s e x p e r i m e n t i s a l s o used on TUMX2071,2411,2412, ana " L a r y e Space Antenna (Ref l e c t o r s ) .I' T e t h e r e d Experiments, TOMX2541-4 - These f o u r e x p e r i m e n t s were n o t p r e s e n t e d a t t h e O A S T In-Space K T & E korkshop, b u t t h e y have d y n a h i c i m p l i c a t i o n s f o r Space S t a t i o n . These m i s s i o n s deirionstrate t h e a p p l i c a t i o n o f t e t h e r t e c h n o l o g y . The first t e t h e r m i s s i o n p r o b a b l y s h o u l d be d e s i g n e d t o demonstrate t e t h e r o p e r a t i o n w i t h a dummy mass. Oynamic S t a b i l i z a t i o n o f a F r e e - F l y i n g Robot, TDMX2433 - T h i s e x p e r i m e n t wds n o t p r e s e n t e d a t t h e OAST In-Space HTBE. korkshop. It denionstrates s t a b i l i t y ana s t a t i o n k e e p i n g t e c h n o l o g y f o r a s e r v i c i n g r o b o t . 3 . 3 . 2 . 3 Space S t a t i o n Dynamic C h a r a c t e r i z a t i o n Advancea C o n t r o l s Technology, TUkX2414 - T h i s experinrerit riiakes use o f t h e Space S t a t i o n and t h e M o b i l e S e r v i c e Center (MSC) t o s t u d y systeni i d e n t i f i c a t i o n and c o n t r o l a l g o r i t h m s f o r l a r g e , f l e x i b l e spdce s t r u c t u r e s . Performance Technology - The Space S t a t i o n s t r u c t u r e Space S t a t i o n System i s i n s t r u m e n t e d t o d e t e r m i n e i t s dynamic c h a r a c t e r i s t i c s d u r i n g b u i l d - u p and post-IOC o p e r a t i o n . 11

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3.3.2.4 Space, C o n s t r u c t i o n Technology S t r u c t u r e s and Assembly V e r i f i c a t i o n E x p e r i m e n t ( S A V ~ ) - S i m i l a r t o " S t r u c t u r a l Assembly E x p e r i m e n t s " p r e s e n t e d a t t h e OAST In-Space K T h E Irorkshop, it deirlonstrates Space S t a t i o n t r u s s c o n s t r u c t i o n . L a r g e Space S t r u c t u r e , TUMX2061 - T h i s m i s s i o n d e n o n s t r a t e s t h e deployment o f a t r u s s p l a t f o r m t o be used as a permanent Space S t a t i o n t a c i l i t y t h e e x p e r i m e n t . The f a c i l i t y ' s - p u r l o s e ( C o n s t r u c t i o n / S t o r a y e / H a n y a r ) a f t e r i s s i m i l a r t o TUMX2062, "Space S t a t i o n Moaif i c a t i o n s .'I Space S t a t i o n M o d i f i c a t i o n s , TOMX2062 - T h i s experirrient adas a " s e r v i c i n y I t s purpose i s s i m i l a r t o TbM)t2061, s u p p o r t area" t o t h e Space S t a t i o n . " L a r g e Space S t r u c t u r e . " On-Orbi t S p a c e c r a f t Assembly and Test, TOMX2063 - The o b j e c t ive o f t h is e x p e r i m e n t i s t o d e m o n s t r a t e Space S t a t i o n c a p a b i 1i t y f o r s a t e 1 1i t e assembly and s e r v i c i n g . L a r g e Space Antenna ( R e f l e c t o r s ) - The antenna hardware i d e n t i f i e u f o r t h i s e x p e r i m e n t i s a l s o used on TOMX2071,2411, 2412, and 2413. E n v i r o n m e n t a l I n f l u e n c e on S t r u c t u r a l Dynamics - T h i s e x p e r i m e n t s t u d i e s t h e e f f e c t s of space exposure on t h e b e h a v i o r o f m a t e r i a l s ana j o i n t s . It c o u l d be combined w i t h TUMX2011, " S p a c e c r a f t M a t e r i a l s and Coatings." P r e c i s i o n O p t i c a l - T h i s e x p e r i m e n t s u p p o r t s LDR t e c h n o l o g y . It i s s i m i l a r t o TURX2421 dnd "TUk f o r LbH," e x c e p t t h a t a ilioaular c o n s t r u c t i o n approacri i s used. TDM t o r LDk - T h i s e x p e r i m e n t s u p p o r t s LUR t e c h n o l o g y . It nay be t h e same e i i s s i o n as Tui-iX2421, " A c t i v e O p t i c Technolog]," a l t h o u g i d i f f e r e n t f l i g h t d a t e s a r e s p e c i f i e d . It i s a l s o s i m i l a r t o t h e " P r e c i s i o n O p t i c a l " exper illlent. I n f l a t a b l e / k l g i d S t r u c t u r e t l e m e n t s , TUClXZUbb - Hri aavdnceci s t r u c t u r a l c o n c e p t i s proposeu as an a l t e r n a t i v e t o c o n v e n t i o n a l c o n s t r u c t i o n methods. I n f l a t a b l e s t r u c t u r e s a r e proposed f o r Space S t a t i o n f a c i l i t i e s such as a i r l o c k s and hangars. SAAX020 - T h i s i s t h e s c i e n c e and L a r g e Deploqable R e f l e c t o r (LDK), a p p l i c a t i o n s m i s s i o n t h a t i s t h e c u l m i n a t i o n of many of t h e T O M X m i s s i o n s . Performlance, TDMX2064 - The o b j e c t i v e o t t h i s Advanced Antenna Assembly and e x p e r i m e n t i s t o d e m o n s t r a t e t h e assembly o f a l a r g e ( 1 0 0 m e t e r d i a m e t e r antenna on t h e Space S t a t i o n . I t s l a r g e s i z e i s t h e volume d r i v e r f o r Space S t a t i o n e x p e r i m e n t s . 3.3.2.5 M a t e r i a l s and F a b r i c a t i o n Technology Mechanisms - The purpose o f t h i s e x p e r i m e n t P o l y m e r i c M a t e r i a l s f o r Space i s t o aeterniine t h e e f f e c t s of space exposure on s e l f - l u b r i c a t i n g p o l y m e r i c 12

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m a t p r i a l s undclr s l i d i n q / r o l l i n q c o n t a c t f o r space mechanisms. It c o u l d bc combined w i t h TI)MX3011, " 5 p a c e c r a f t M a t e r i a l s and C o a t i n q s . " S p a c e c r a f t P a t e r i a l s and Coatings, TDMX2011 - This i s a l o n g t e r m exposure e x p e r i m e n t t o s t u d y t h e e f f e c t s of t h e space environment on m a t e r i a l s and c o a t i n g s . It was p r e s e n t e d i n t h e Space E n v i r o n m e n t a l E f f e c t s theme a r e a a t t h e Workshop. M i c r o m e t e o r i t e P r o t e c t i o n - T h i s i s an e x p e r i m e n t t o i n v e s t i g a t e m i c r o m e t e o r i t e p r o t e c t i o n techniques. No d e t a i l s were p r e s e n t e d . I o n Beam Cold Welding, TDMX2065 - T h i s e x p e r i m e n t demonstrates t h e use o f i o n beam c o l d w e l d i n g t e c h n i q u e s f o r f a b r i c a t i n g l a r g e s t r u c t u r e s i n space. 3.3.2.6 S t r u c t u r a l Concepts Research F a c i l i t y This i s a Space S t a t i o n f a c i l i t y proposed f o r t h e advancement o f s t r u c t u r a l concepts f o r f u t u r e s o a c e c r a f t . The low-g e n v i r o n m e n t i s i d e a l f o r t e s t i n g s t r u c t u r a l components and a s s e m b l i e s t h a t cannot be t e s t e d a d e q u a t e l y i n 1-g. It a l s o c o u l d be used t o e v a l u a t e m a t e r i a l s and c o a t i n g s f r o m T D M X 2 O l l . 3 . 4 Technology Gaps One of t h e t a s k s of t h e Space S t r u c t u r e (Dynamics 8 C o n t r o l ) themearea o a n e l a t t h e O A S T In-Space RT&E Workshop was t o i d e n t i f y t e c h n o l o g y gaps based on t h e e x p e r i m e n t s presented. A m a t r i x was c r e a t e d whose rows a r e t h e proposed e x p e r i m e n t s , and whose columns a r e t e c h n o l o g y areas o f i m p o r t a n c e t o t h e theme a r e a . The t e c h n o l o g y areas t h a t a r e n o t a d e q u a t e l y addressed by t h e e x p e r i m e n t s were i d e n t i f i e d and p r e s e n t e d i n t h e Workshop d o c u m e n t a t i o n . D u r i n g t h i s s t u d y , t h e m a t r i x was expanded t o i n c l u d e the TDMX m i s s i o n s t h a t were n o t p r e s e n t e d a t t h e Workshop. A l l of t h e m i s s i o n s were r e v i e w e d t o v e r i f y t h e p a n e l ' s assessment and t o expand it t o i n c l u d e o m i t t e d and secondary t e c h n o l o g y goals f o r each o f t h e e x p e r i m e n t s . The 37 t e c h n o l o g y t o p i c s i d e n t i f i e d b y the Workshop p a n e l were grouped i n t o s i x c a t e g o r i e s : sensors, c o n t r o l devices, c o n t r o l t e c h n i q u e s , dynamics, m o d e l i n a , and s t r u c t u r e s and m a t e r i a l s . The r e s u l t i n g t e c h n o l o g y assessment m a t r i x i s shown i n f i g u r e 3.4-1. Ry o b s e r v i n g t h e number o f X ' s i n each column ( t e c h n o l o g y a r e a ) , t h e t e c h n o l o g y gaps and t h i n s p o t s were i d e n t i f i e d . The d e t e r m i n a t i o n of t e c h n o l o g y gaps and t h i n s p o t s i s accomplished i n two s t e p s . F i r s t , t h e Workshop p a n e l ' s assessment of t h e t e c h n o l o g y gaps a d d i t i o n a l TDMX m i s s i o n s i n c l u d e d i n t h e l i s t . i s r e v i e w e d c o n s i d e r i n g t h e Then, o t h e r t e c h n o l o g y needs a r e determined based on t h e updated t e c h n o l o g y m a t r i x . 1 3

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3.4.1 O A S T In-Space K T & E Workshop P a n e l ' s Assessment t a c h of t h e t e c h n o l o y y areas i u e n t i f i e d b y t h e O A S T In-SGace c t T & t korkshop p d n e l as r e q u i r i n g a d d i t i o n a l a t t e n t i o n a r e r e v i e w e o i n t h e t o 1 l o w i n g parayraphs. The coitiments f o l l o k i n g each t o p i c r e f l e c t t h e i n c l u s i o n o f TIJf4X e i i s s i o n s t h a t were n o t i n c l u a e a i n t h e korkshop r e v i e w . Val i d a t i o n o t Space S t a t i o n s t r u c t u r e ( c o n s t r u c t i o n t e c h n i q u e s , u t i l i t y i n t e g r i t y ) - The S t r u c t u r e s and Assembly i n t e g r a t i o n , l o n g - t e r n ; V e r i f i c a t i o n Experiment ( S A V E ) addresses t h i s need. however, e x p e r i m e n t s t o demonstrate o t h e r a s p e c t s of Space S t a t i o n c o n s t r u c t i o n a r e needed (e.g., module attachment, equipment and subsystem i n s t a l l a t i o n , e t c . ) . A l t h o u g h i n a d i f f e r e n t theme area, r o b o t i c assembly t e c h n o l o g y s h o u l d be i d e n t i f i e d as an i m p o r t a n t r e q u i r e m e n t f o r f u t u r e i n - s p a c e c o n s t r u c t i o n . The dynamics and c o n t r o l o f r o b o t s must be u n d e r s t o o d . P o t e n t i d l Space S t a t i o n d i s t u r b a n c e caused by r o b o t i c assembly i s a l s o a s i g n i f i c a n t concern. c h a r a c t e r i z a t i o n - S t r u c t u r a l l o a d s w i l l be measured on COFS I n - s p a c e l o a a s and SAVE. Space S t a t i o n loads environments f o r e v e n t s such d s d o c k i n g ana r e b o o s t w i l l be measured d u r i n g t h e Space S t a t i o n S t r u c t u r a l L h a r a c t e r i z a t i o n Experiment. P a s s i v e damping - k i t h p r o p e r i n s t r u m e n t a t i o n , a s - b u i It s t r u c t u r a l damping measured d u r i n g e x p e r i m e n t s such as COFS, S A V L ana c h a r a c t e r i s t i c s can be TDPis f o r LDR. w e s i y n e a - i n p a s s i v e aainping e x p e r i m e n t s a r e neeaeu t o v e r i t y damping d e s i g n s ana t o v a l i d a t e ground t e s t s ana a n a l j s i s . P a s s i v e damping by t h e A i r F o r c e (PACOSS, KELSAT, e t c . ) s t u d i e s a r e c u r r e n t l y b e i n g funaea tnibedded sensors and a c t u a t o r s - These s h o u l a be developea dna v a l i d a t e d u s i n g ground t e s t s . They have wide a p p l i c a t i o n s f o r inany t y p e s o f space s t r u c t u r e $ . Embedded sensors should be developed e a r l y t o s u p p o r t Space S t a t i o n and o t h e r e x p e r i m e n t s . V i b r a t i o n c o n t r o l Gevices - Some a c t i v e v i b r a t i o n c o n t r o l d e v i c e s a r e b e i n g a e v e l o p e d ( p r o o f mass a c t u a t o r s , p i e z o - e l e c t r i c d e v i c e s , e t c . ). Proof-mass a c t u a t o r s w i 1 1 be used on COFS I . Shape c o n t r o l d e v i c e s - Shape c o n t r o l o f t h e 15-meter hoop-column antenna i s b e i n g developed a t Lakc. Techniques arid d e v i c e 5 f o r t h e c o n t r o l o f need t o be s t u d i e a arid deiiiorlstrated. The o t h e r t y p e s ( J f r e f l e c t o r s u r t a c e s embedded sensor and a c t u a t o r s mentioned above a r e p r i m e c a n d i d a t e s . Low f r e q u e n c y v i b r a t i o n i s o l a t o r s - A i r Force s t u d i e s a r e i n p r o y r e s s t o d e v e l o p low f r e q u e n c y v i b r a t i o n i s o l a t o r s and p o i n t i n g systems. F l u i d - s t r u c t u r e i n t e r a c t i o n - D i s t u r b a n c e s r e s u l t i n g froin f l u i a - s t r u c t u r e i n t e r a c t i o n may be a s i g n i f i c a n t c o n t r i b u t o r t o Space S t a t i o n , OrVrV dnd O T V dynamics and c o n t r o l . O r b i t e r f l i g h t e x p e r i m e n t s would be v a l u a b l e , s i n c e ground t e s t s cannot a d e q u a t e l y aupl i c a t e t h e m i c r o - y e n v i r o n m e n t . Advanced s t r u c t u r a l c o n c e p t s - Aavanced s t r u c t u r a l ineiiibers, elements, j o i n t s , s u r f a c e s , c o n s t r u c t i o n techniques, e t c . need t o be aeveloped ana aenionstrated.

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In-space fabrication - The only experiment currently being considered in this area is "Ion Beam Cold Welding" (TDMX2065). On-orbit fabrication technology (e.g. beam-bui lders) needs to be revived an3 advanced for future large space structures. Docking/berthinq sensors - One such experiment has been suggested. Other candidates need to be designed and developed. Orbiter flight experiments should he defined to demonstrate the capability for Space Station. faci 1 ity - A permanent Space Station facility Structural development/test is needed to provide the low-g and other environmental conditions required t o characterize new sensors, actuators and advanced structural concepts. 3.4.2 Other Technoloay Concerns The technology matrix (figure 3 . 4 . - 1 ) indicates other areas that need to be addressed to advance the technologies for future space systems: Low cost concept - No experiments explicitly identify this as a technical objective, but it is a goal for all space systems. O R U concepts - Orbital replacement units ( O R U s ) are becoming a reauirement on-orbit servicing. The design of "standard" for more spacecraft to permit ORUs and interfaces is an important method of reducing the cost of future space systems. The Space Station goal of commonality will promote the development o f low cost O R U s . Attitude control devices - Some magnetically-suspended reaction wheels have been developed, and magnetic suspension C M G ' S are being studied; but other types of devices (e.g., low level thrusters) need to be developed. Failure detection and isolation - Flight experiments are needed to demonstrate techniques currently being developed. System reconfiguration to accommodat.e the loss of one or more sensors is an important aspect of this technology. Precision station keeping - Advancement o f this technology i s a requirement for M M U and O W proximity operations at. the Space Station. Hierarchical control - Coarse and fine control techniques are needed for 'LDR and other instruments and experiments that require precision pointing. Multi-loop control - Advancement in this technology area is needed t o control the various systems for Space Station and other future spacecraft. Maneuvering techniaues - The operation of the MSC (mobile service center) will require this technology to transport objects from place to place on the Space Station., OMV operations will also require maneuvering techniques. 16

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Tether dynamics - Four experiments (TDMX2541-4) are defined whose primary objectives are to demonstrate tether applications rather than the determination of tether dynamics and its effect on the Space Station. Joint modeling - The dynamics of joint-dominated structures are a function analysis methods and test procedures of the joint characteristics. Joint are currently being developed at N A S A and under N A S A contracts. On-orbit verification of these techniques for specific types of structural joints will be accomplished with the COFS and S A V E experiments. Environmental modeling - Three experiments will contribute to the definition of the Space Station environment: "Spacecraft Materials and Coatings" (TDMX20111, "Micrometeorite Protection" and "Environmental Influence on Structura 1 Dynamics .I' Other measurements o f the Space Stat ion environment will be accomplished in the Space Environmental Effects theme area. Disturbance characterization - Knowledge of the potential disturbances for Space Station is required to auantify the environment for experiments, particularly those that require micro-gravity.

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4.0 Recommended E x p e r i m e n t a l A c t i v i t i e s The r e v i e w and e v a l u a t i o n o f on-going and prnposed i n - s p d c e e x p e r i m e n t a t i o n l e a d s t o t h e i d e n t i f i c a t i o n o f a proposed r o a d map f o r t e c h n o l o g y i n t h e Space S t r u c t u r e (Dynamics and C o n t r o l ) theme area. F i r s t , near-term and l o n g - t e r m t e c h n o l o g y g o a l s d i c t a t e a p r i o r i t i z a t i o n of t e c h n o l o g y t o p i c s . Second, t h e p r i o r i t i z a t i o n h e l p s t o d e f i n e a t i m e t a b l e f o r space experiments needed t o demonstrate t h e t e c h n o l o g y areas. And, f i n a l l y , t h e scope of t h e proposed e x p e r i m e n t s r e s u l t s i n i n t e r r e l a t i o n s h i p s w i t h experiments w i t h i n t h i s theme area and t o o t h e r t e c h n o l o g y theme areas. 4 . 1 P r i o r i t i z a t i o n o f Technology Areas Ry r e v i e w i n g t h e t e c h n o l o g y needs f o r Space S t a t i o n and o t h e r n e a r - t e r m missions, a p r i o r i t i z a t i o n of t e c h n o l o g y t o p i c s was e s t a b l i s h e d . T h i s was accomplished by experienced p e r s o n n e l i n b o t h t h e s t r u c t u r a l dynamics and c o n t r o l s t e c h n o l o g y areas. The p r i o r i t i z a t i o n i s shown i n F i g u r e 4 . 1 - 1 . I n some cases, t h e p r i o r i t y i s based on t h e need of t h e t e c h n o l o q y i n the near f u t u r e . I n o t h e r cases, t h e p r i o r i t i z a t i o n i s t h e r e s u l t o f an assessment of t h e l a c k of e x i s t i n g t e c h n i c a l m a t u r i t y . Even though some missions may occur i n t h e f a r f u t u r e , t h e development o f t h e r e q u i r e d t e c h n o l o g i e s needs t o s t a r t now. Some of t h e e x p e r i m e n t s i n t h e l i s t have been grouped i n t o broader c a t e g o r i e s t o ease t h e c o m p l e x i t y and d i f f i c u l t y o f p r i o r i t i z a t i o n . W i t h i n c r e a s i n a s i z e and f l e x i b i l i t y of f u t u r e s p a c e c r a f t , t h e h i g h e s t p r i o r i t y technology area i s a s s o c i a t e d w i t h t h e a b i l i t y t o c h a r a c t e r i z e and c o n t r o l l a r g e f l e x i b l e s t r u c t u r e s . The dynamic c h a r a c t e r i s t i c s o f d e p l o y a b l e s t r u c t u r e s a r e dominated by t h e b e h a v i o r of t h e many j o i n t s t h a t p e r m i t i t s deployment. The t h r e e phases of t h e COFS proqram, i n c l u d i n g t h e g u e s t i n v e s t i q a t o r program, w i l l advance t h e t e c h n o l o q y i n t h i s area, and w i l l demonstrate t h e t e c h n i q u e s needed f o r Space S t a t i o n and o t h e r l a r g e space systems. The n e x t two experiments on t h e p r i o r i t i z e d l i s t d e a l w i t h t h e a b i l i t y t o p e r f o r m s t r u c t u r a l assembly i n space. Two O r b i t e r - b a s e d e x p e r i m e n t s ( F A T E and ACCFTC) have a l r e a d y been conducted t h a t demonstrate s t r u c t u r a l assembly u s i n o F V A . 5 A V F i s a n o t h e r O r b i t e r f l i g h t e x p e r i m e n t t h a t w i l l demonstrate t h e F V A assembly o f t h e 5-meter t r u s s and u t i l i t y t r a y i n t e g r a - t i o n f o r t h e ?pace ? t a t i o n . I n t h e l o n g run, t h e a o a l f o r in-5pace assembly i s t o use r o b o t i c s t o e l i m i n a t e t h e p o t e n t i a l hazards of E V A . A l t h o u g h Automation and R o b o t i c s i s a s e p a r a t e theme area, t h e r o b o t i c o r t e l e r o b o t i c aspects o f t h e O n - o r b i t S p a c e c r a f t Assembly and Test e x p e r i m e n t a r e h i g h on t h e p r i o r i t y l i s t t o advance t h e a b i l i t y t o a n a l y z e and p r e d i c t t h e b e h a v i o r of c o n t r o l l a b l e , m u l t i - b o d y , j o i n t e d s t r u c t u r e s . Next. on the p r i o r i t y l i s t a r e two e x p e r i m e n t s i n t h a t address component technology. Advanced c o n t r o l d e v i c e s a r e needed t o implement t h e t e c h n i q u e s developed t o c o n t r o l l a r g e f l e x i b l e space s t r u c t u r e s and t h e Space S t a t i o n . Advanced experiment p o i n t i n g and i s o l a t i o n systems a r e

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Figure 4.1-1: Structures/Dynamics/Controls Technology Priorities Priority Experiment 1?ontrol of tlexible Structures (Cots) 2 Structures and Assembly Verification Experiment (SAVE) 3 On-Orbit Spacecraft Assembly and Test (Robotics) 4 Component Technology Advanced control devices Advanced experiment pointing and isolation 5 Materials Technology Materials and coatings Polymeric materials for space mechanisms influence on structural dynamics Environmental 6 ?pace Station Performance Experiment 7 Space Station Facilities Large space structures Space Station modifications Structural Concepts Research Facility 8 Large Deployable Reflector (LDR) TDM for LDR Precision optical Active optic technology 9 Component Technology Dock i ng/ berth i ng Sensor Structura 1 ly embedded sensors and actuators Attitude control and energy flight experiment Thermal shape control 10 4ntenna Fx per iments Large space antenna (reflectors) Advanced adaptive control 1) i str ibuted contro 1 exper iment 13ynamic disturbance control Advanced a n tenna assemb 1y/test 11 Advanced Controls Technology 1 2 Tethered Experiments 1 3 In-Space Fabrication I o n beam cold weld 1 4 lnf latable/Rigid StFuctural Elements 19

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needed to provide pointing accuracy and stability for spacecraft and experiments mounted on the Space systemslcomponents and for antennas Station. The fifth item on the list includes several experiments whose goal is to determine the behavior of materials in the space environment dnd to develop durable and stable materials and coatings for space applications. Althouah the influence o f the spacc! environment on materials is extremely important and should be pursued, many of the major effects o f the space environment have already been identified (not necessarily quantified), however, there are materials that are able to withstand the space environment. Also, the methods for in-space experimentation require little technological advancement. The next three items relate to the characterization and assembly of large space structures such as the Space Station, its evolutionary features, and the large deployable antenna ( L D R ) . The Space Station should be instrumented to determine its dynamic behavior during the many stages of assembly. This will provide data for the verification of ground tests and analysis techniques. 'Through the addition of new Space Station facilities, additional knowledge of in-space assembly will be obtained. Construction of LDR will not only advance the technology for both E V A and robotic structural assembly, but also for alignment and control of a high precision, segmented reflector surface. Prioritization o f the remainder of the experiments becomes more and more difficult and subjective. Advancement of sensor and actuator technology is highly desirable and docking and berthing sensors will be today's technology is judged to be required for Space Station, but sufficient with the current rate of advancement. Advancement o f some of antenna systems will occur as a result o f the technologies needed for large the higher priority technology topics for the control of flexible structures. Application of the technologies for tether systems, in-space fabrication and advanced structural concepts will require an operational Space Station and are, therefore, lower priority. I n summary, all of the technology development experiments and topics listed are vital to the advancement of the Space Structure (Dynamics and Control) theme. Development of the technologies for all of the experiments should continue. The priority for the development of some smaller experiments ( e . a . , sensors, actuators, control techniques, etc.) could be found on a higher priority mission. raised if an application can be 4 . 2 Experiment Timetable The identification of a technology timeline was accomplished by the theme panel at the O A S T In-Space RT&E Workshop in October, 1985, and is 20

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shown i n F i g u r e s 4.2-1 t h r o u g h 4.2-5 f o r t h e f i v e areas w i t h i n t h e theme area. W i t h p r o p e r a d j u s t m e n t s t o account f o r t h e s l i d e i n t h e d a t e of Space S t a t i o n IOC, t h e f l o w of t e c h n o l o g y development shown i s a c c u r a t e . A more e x p e r i m e n t - o r i e n t e d t i m e t a b l e i s p r e s e n t e d here, based on t h e p r i o r i t i z a t i o n of t h e e x p e r i m e n t s shown above and on a model s e t o f TDMX m i s s i o n s l i s t e d i n F i g u r e 4.2-6. T h i s m i s s i o n model i s a r e f e r e n c e s e t o f e x p e r i m e n t s p r o v i d e d t o Code S ( O f f i c e of Space S t a t i o n ) b y Code R ( O f f i c e of A e r o n a u t i c s and Space Technology) s o t h a t an e a r l y assessment of Space S t a t i o n accommodation r e q u i r e m e n t s can be made. They r e p r e s e n t t h e t y p e s o f e x p e r i m e n t s t h a t c o u l d be conducted i n t h e near-10C timeframe ( w i t h i n t h r e e y e a r s f o l l o w i n g IOC). F i g u r e s 4.2-7 t h r o u g h 4.2-9 p r e s e n t t h e recommended i n - s p a c e e x p e r i m e n t a c t i v i t y f o r t h e l a t e 19OO's, assuming t h a t Space S t a t i o n I O C w i l l be i n 1995. The proposed e x p e r i m e n t s were c a t e g o r i z e d , a c c o r d i n g t o t h e i r p r i m a r y o b j e c t i v e , i n t o t h r e e c a t e g o r i e s : s t r u c t u r e s , c o n t r o l / s t r u c t u r e i n t e r a c t i o n , and c o n t r o l s . Each f i g u r e l i s t s e x p e r i m e n t s whose p r i m a r y and secondary o b j e c t i v e s a r e i n t h a t c a t e g o r y . Comments a r e a l s o p r o v i d e d t o i n d i c a t e m i s s i o n s t h a t have a l r e a d y f l o w n and e x p e r i m e n t s t h a t a r e s i m i l a r o r use t h e same hardware. Many of t h e e x p e r i m e n t s would b e n e f i t f r o m p r e c u r s o r S h u t t l e e x p e r i m e n t s , some o f which a r e i d e n t i f i e d i n t h e f i g u r e s . 4 . 3 I n t e r r e l a t i o n s h i p o f A c t i v i t i e s It i s c l e a r t h a t many experiments span s e v e r a l t e c h n o l o g y a r e a s , no m a t t e r what c a t e g o r i e s a r e used. For example, a l l of t h e e x p e r i m e n t s need some k i n d o f s t r u c t u r e . Therefore, t h e c o n s t r u c t i o n of t h e t e s t a r t i c l e w h i l e t h e p r i m a r y purpose o f t h e e x p e r i m e n t f a l l s i n t o t h e s t r u c t u r e s area, t e c h n o l o g y . So t h e r e i s a g r a t amount o f may be t o demonstrate c o n t r o l s Also, even though r o b o t i c s t e c h n o l o g y i s s y n e r g i s m among t h e e x p e r i m e n t s . of t h e r o b o t i c s t r u c t u r e i s an a s e p a r a t e theme area, t h e dynamics i m p o r t a n t f a c t o r i n d e t e r m i n i n g i t s performance. c o o r d i n a t i o n , t h e o b j e c t ves of s e v e r a l By c a r e f u l p l a n n i n g , d e s i g n and s i n g l e t e s t a r t i c l e . F o r example, t h e e x p e r i m e n t s may be r e a l i z e d w i t h a s e r i e s o f antenna e x p e r i m e n t s p r o p o s e d - b y JPL have been p l a n n e d so t h a t t h e same antenna s t r u c t u r e w i l l be used f o r s e v e r a l of t h e e x p e r i m e n t s . Also, as p r e v i o u s l y mentioned, some s m a l l e r e x p e r i m e n t s t h a t d e m o n s t r a t e sensors, a c t u a t o r s , and c o n t r o l t e c h n i q u e s can be combined w i t h l a r g e r e x p e r i m e n t s t o enhance t h e i r p o s i t i o n i n t h e stream o f t e c h n o l o g y development. 2 1

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Figure 4.2-1: Component Technology GwHmtlnSTATION 0 DYNAUIC ISOLATORS o LUBRICATION UETHODS o DOCKlNQlROTATlON ULCHANISUS o ADVANCED ACTUATORSISENSORS o PRECISION POlNTlNQ SYSTEU 1985 1990 1995 Figure 4.2-2: ControVStructures Interaction (CSl) TECIIWOLOOV LEVEL 1985 SPACE STATION CSI EXPER. o ANTENNAS o ACTIVELY CONTROLLE PLATFORUS o ROBOTS o ARTICULATED ACTIVELY-CONTROLLED IOC 1990 1995 22

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Figure 4.2-3: Space Station Dynamic Characterization GROWTH STATION EXPERIUENTS 0 TANKAGE DYNAUICS o ROTATINO FLUID-STRUCTURE DYNAUICS OF IOC 0 UEAS. DURINO CONSTRUCT. 0 LIFE ASSESSMENT (NDE) SYSTEM DEMO. OND. TESTS OEVEL o CONTROL EXP. IOC 1985 1990 1995 Figure 4.2-4: Construction Technology LARGE STRUCTURES ON-ORBIT ASSEMBLY AND CHECK-OUT o ANTENNAS o PLATFORUS CONBTRUCTION VALIDATION EXPERIUWTB 0 UTILITY INTEORATION 0 ERECTABLEIDEPLOYABLE 0 GROUNDIIM-SPACE CORRELATION UENTS J STRUCTURAL 1oc I I I 1985 1990 1995 23

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Figure 4.2-5: Advanced Structural Concepts DESIGN CONCEPTSIGROUND TESl o INFLATABLES o OEODESIC FRAMES o JOINTS o DEBRIS PROTECTION 0 ANTENNAS O WRAP-RIB 0 tI0OP o LDR c 1985 SPACE-SmTION- BASED ON-ORBIT STRUCTURAL FABRICATION 0 ON-ORBIT COMPOSITE CURlNGlFORUlNQ 0 MEMBRANES o INFLATABLES 0 NONTERRESTIAL STRUCTURAL FABRICATION 0 SEGMENTED REFLECTORS IOC 1990 1995 Figure 4.2-6: TDMX Model Set lmK!!b SDonsor Flight Dynamics Identification JPL 2 0 7 1 2 4 1 1 Advanced Adaptive Control JPL 2 4 1 2 Experiment JPL Distributed Control Dynamic Disturbance Experiment JPL 2 4 1 3 Microelectronics Data System Experiment JPL 2 4 4 1 2 4 6 2 Dextrous Teleoperator Technology JPL Teleoperated Structure Assembly JPL 2 4 6 1 Advanced Radiator Concepts LeRC 21 3 2 Advanced Solar Dynamic Power LeRC 2 1 5 3 Long-Term Cryogenic Fluid Storage LeRC 2 3 1 1 Spacecraft Materials and Coatings LaRC 2 0 1 1 Spacecraft Strain and Acoustics Sensors h R C 2 0 7 2 Space Station Structural Performance Experiment LaRC SPE Transient Upset Phenomena in VLSl Devices LaRC 2 4 4 2 VHSlC Fault Tolerant Processor LaRC 2 4 4 3 2 5 6 1 Satellite Servicing and Refurbishment MSFC 2 5 6 2 Satellite Maintenance and Repair MSFC Transfer/Storage/Reliquifaction MSFC 2 5 7 2 Cryogenic Propellant 2 5 7 3 OTV Docking and Berthing MSFC 2 5 7 4 OTV Maintenance Technology MSFC 2 5 7 1 OTV/Payload Interfacing and Transfer MSFC 24

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1 I I I LC I ! L C . L L I If c a n a n urt r a L Y- u n Qz W lan U a W VI W a a a + r Va a a c c VI U a a C C C C IL C & Y cal - .- Lal 0 I W Y c 0- .L CIY L 0ul L U=I a l a l 9m Lu - n x w c 0 Y Um L ualWY Ya l -C - a l a V L3 - 4 . I Eo sU C LulY - V I L \0 - 3LoL W Y & e c o 5 % Ual 2 5

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2 cn c wz a r a e a w a n a I W r z a = c a uU a Y wc a z I . a Ia r a a c a aa a u ca4 0 .- La4 n E I I I + rL 0 er, Ya4 m U Y ca4 La4 'cY .- U m c .- 01L m m a4W 26

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L 0m L=I U m a l a Lma 1 m r E L0 c Yal 0. c Yal a m U al U Y m .. c v )U al L r 4I al al -4- -.- L 2m U al La m c 0.a 4 !? m LL w al Lm U U Imal 3 UL > d cn YU 0m al -? d m m0 0)al 0)I .- '" L a. al 27

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5.0 Summary and C o n c l u s i o n s Long range t e c h n o l o g y o b j e c t i v e s and g o a l s w i t h i n t h e Space S t r u c t u r e (Dynamics and C o n t r o l theme area were i d e n t i f i e d based on proposed s p a c e c r a f t and m i s s i o n s . C u r r e n t N A S A a c t i v i t i e s w i t h i n t h e theine area F l i s s i o n Requirements Data Rase (MRIIR) and were reviewed. The Space S t a t i o n t h e r e s u l t s o f t h e O A S T In-Space Research, Technology and E n g i n e e r i n g (RT&E) Workshop were a l s o r e v i e w e d t o e v a l u a t e a c t i v i t y t h a t has been proposed w i t h i n t h e theme area. As a r e s u l t o f t h i s e v a l u a t i o n , t e c h n o l o g y areas t h a t need more a t t e n t i o n t o a c h i e v e t h e l o n g - r a n g e g o a l s were i d e n t i f i e d . P r i o r i t i z a t i o n of t e c h n o l o g y t o p i c s w i t h i n t h e theme a r e a was accomplished t o a i d i n t h e development of an e x p e r i m e n t t i m e t a b l e f o r t h e l a t e 1900's. This t i m e t a b l e i s , o f course, v e r y t e n t a t i v e f o r two reasons: t h e u n c e r t a i n t y o f t h e Space S h u t t l e f l i g h t s c h e d u l e and t h e Space S t a t i o n c o n s t r u c t i o n schedule. The a v a i l a b i l i t y of t h e S h u t t l e t o b e g i n Space S t a t i o n c o n s t r u c t i o n w i l l depend on t h e r e d e s i g n a c t i v i t y r e s u l t i n g f r o m t h e C h a l l e n g e r a c c i d e n t . The c o n s t r u c t i o n of t h e Space S t a t i o n must a l s o p r o g r e s s t o a p o i n t such t h a t t e c h n o l o g y development e x p e r i m e n t s can be accommodated. I n g e n e r a l , t h e e x p e r i m e n t s proposed i n t h e Space S t a t i o n M i s s i o n Requirements Data Rase (MRDB) and t h e O A S T In-Space RT&E Workshop c o v e r a wide range of t o p i c s i n t h e Space S t r u c t u r e (Dynamic and C o n t r o l ) theme a r e a and c o n s t i t u t e a comprehensive p l a n f o r t h e d e m o n s t r a t i o q o f t e c h n o l o g i e s r e q u i r e d f o r f u t u r e space m i s s i o n s . There a r e many d u p l i c a t e o r complementary o b j e c t i v e s among t h e e x p e r i m e n t s . There are, however, s e v e r a l areas t h a t r e q u i r e more a t t e n t i o n , p a r t i c u l a r l y i n t h e d e f i n i t i o n of i n - s p a c e d e m o n s t r a t i o n e x p e r i m e n t s . These t e c h n o l o g y areas i n c l u d e b e r t h i n g / d o c k i n g sensors, O R U concepts, p r e c i s i o n s t a t i o n k e e p i n g and p r o x i m i t y o p e r a t i o n s , m u l t i - l o o p c o n t r o l , h i e r a r c h i c a l c o n t r o l , j o i n t modeling, d i s t u r b a n c e c h a r a c t e r i z a t i o n and p a s s i v e damping. C o o r d i n a t i o n between e x p e r i m e n t s w i t h i n t h e Space S t r u c t u r e (Dynamics and C o n t r o l ) theme area and a l s o between theme areas s h o u l d be accomplished whenever p o s s i b l e t o make maximum use o f t h e Space S t a t i o n r e s o u r c e s . F o r example, some of t h e smal l e r e x p e r i m e n t s ( s e n s o r s , a c t u a t o r s , s t r u c t u r a l j o i n t s , dampinq, e t c . ) c o u l d be c o n s o l i d a t e d w i t h l a r g e r ones t o enhance t h e i r p r i o r i t y , a n d a t t h e same t i m e s e r v e t o b e n e f i t t h e l a r g e r e x p e r i m e n t . Fxperirnents t h a t u t i l i z e common o r s i m i l a r hardware, t h a t have s i m i l a r o b j e c t i v e s o r t h a t complement each o t h e r , s h o u l d be combined i n t o t e s t b e d s whenever p r a c t i c a l . An example o f i n t e r - t h e m e c o o r d i n a t i o n i s i n t h e area of r o b o t i c s . Space S t r u c t u r e (Dynamics and C o n t r o l ) and R o b o t i c s a r e s e p a r a t e theme areas, b u t t h e dynamics and c o n t r o l o f r o b o t s i s an i m p o r t a n t issue, and r o b o t i c s i s e n v i s i o n e d as a p r i m e c a n d i d a t e f o r assembling s t r u c t u r e s i n space. T h e r e f o r e , c o o r d i n a t i o n between two o r more theme areas i s r e q u i r e d f o r some e x p e r i m e n t s . 28

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6.0 Acknowledgments acknowledge t h e f o l l o w i n g f o r t h e i r s u p p o r t The a u t h o r s g r a t e f u l l y d u r i n g t h i s a c t i v i t y . It was t h e i r r e v i e w , e v a l u a t i o n s and assessments t h a t t h e r e s u l t s were g e n e r a t e d and L a n a l e v Research Center M i c h a e l F . Card Claude R . K e c k l e r completed i n a t i m e l y manner. Boeing Aerospace Company Roy Ikegami Dean J a c o t 29

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Report Documentation Page I I 4’. . i Government Accession No 3. Recipient‘s Catalog No. 1 1 Report NO I 2 I NASA TM-100597 4 ~ i t i r !incl s u t i ~ i t ~ ~ . . ..... ~ - 5 Report Date August 1988 Space Structure (Dynamics and Control ) Theme Development 1 Richard A . Russell and Richard M. Gates NASA Langley Research Center Harnpton, Va. 23665-5225 . _ _ - 1 6--SFisonncJxgency Name and Address National Aeronautics and Space Administration Washington, D . C . 20546-0001 . - 15 Supplementary Notes I - - 6 PtdormiGg Organtiation-Code __ _- - - 8. Performing Organization Report No. - 10. Work Unit No. 506-49-31-02 .__ __ 11. Contract or Grant No. 13. Type of Report and Period Covered Technical Memorandum 14. Sponsoring hgency Code Richard A. Russell, Langley Research Center, Hampton, Va. Richard M. Gates, Boeing Aerospace Company, S e a t t l e , Wa. - - . . _- 16 Abstract A study was performed t o define the long-ran e technical objectives and goals f o r the Space Structure (Dynamics & Control 3 theme area. The approach was t o evaluate on-going and proposed technology a c t i v i t i e s such that the technology gaps a n d voids could be identified. After the technology needs were identified, a s e t of recommended experimental a c t i v i t i e s were defined including the technical objectives of each and t h e i r interrelationship. ~-- ___.-- 17 Key Words (Suggested by A u t h o r k ) ) Space Structures Control/Structure Interaction F1 ight Experiments Control s 18. Distribution Statement Unclassified-Unl imited Subject Category: 18 ____ 19 Security Classif ( o f this report) 20 Security Classif (of this pagel 2 i NO of pages - 22 Price Uncl a s s i f i ed Uncl assi f ied 31 A03